This invention relates to improved nozzles for use with abrasive and/or corrosive materials, and more particularly to nozzles of reduced wear rate and cost for use in industry anywhere there is an abrasive and/or corrosive material to be discharged through a nozzle.
Many industrial processes require discharging an abrasive and/or corrosive fluid under pressure through a nozzle. The wear rate of the nozzle is often so high that the current practice is to employ silicon or tungsten carbide (which are among the hardest known substances) for the nozzles, and to periodically replace the nozzles. For example, heavy duty sandblasting nozzles are presently made of tungsten carbide with steel casings. Such nozzles cost about $100 and have a limited life of about 200 hours. Wear of the nozzle results in gradual reduction of sandblasting effectiveness in that as the orifice increases in size, the velocity of the air and sand decreases. At the same time the area covered by the nozzle spray expands. To maintain operator effectiveness, frequent replacement of the nozzle is required.
Assuming several million sandblast nozzles are consumed annually in just the United States, an improvement which extends the life of the nozzle and reduces their unit cost would result in a direct saving to the industry of millions of dollars in just the nozzles alone. Additional savings would be realized from higher lifetime effectiveness (i.e., greater operator productivity) and a significant reduction in lost time involved in replacement of nozzles.
Another example is paint spraying. Because metal oxides are abrasive, and paints are generally mixtures of metal oxides in a liquid vehicle, paint spray guns are made with replaceable silicon carbide tips (nozzles). As the tip wears, there is a degradation of the spraying process and loss of operator effectiveness. This requires more skill on the part of the operator, or more frequent replacements. Since each replacement involves loss of productive time, there is a net loss in production due to wear even with more frequent replacements.
Still another example is oil drilling in which the drill bit is continually washed with drilling mud in the drilling process. As the nozzle for the drilling mud wears, the effectiveness of the washing process decreases. In order to maintain high effectiveness, and thereby minimize wear of the drill bits themselves, it is necessary to replace the drilling mud nozzle frequently, but that involves loss of drilling time.
There are still other examples that could be enumerated that involve abrasive and/or corrosive wear, such as steam nozzles. The few that have been enumerated are not intended to be all inclusive. Consequently, although the following description of specific embodiments will be with reference to some of these examples, it is understood that such examples are not intended to be limitative of the invention.